Generate HTML5 Cache Manifest files. Submitted by Scott Hillman.

Big thanks to Gunther Brunner for writing the grunt-manifest plugin. This plugin was heavily influenced by his great work.

Visit the HTML 5 Guide to AppCache for more information on Cache Manifest files.

First, install gulp-manifest as a dev dependency

npm install gulp-manifest --save-dev

This controls how this task (and its helpers) operate and should contain key:value pairs, see options below.

Type: String Default: undefined

Add a prefix to the file paths. Useful when your files are in a different URL than the page.

Type: String
Default: undefined

Add a suffix to the file paths. Useful when your files have query string.

Type: String Default: 'app.manifest'

Set name of the Cache Manifest file.

Type: String Array Default: undefined

Adds manually a string to the CACHE section. Needed when you have cache buster for example.

Type: String Array Default: undefined

Exclude specific files from the Cache Manifest file.

Type: String Array Default: '*' (By default, an online whitelist wildcard flag is added)

Adds a string to the NETWORK section.

See here for more information.

Type: String Array Default: undefined

Adds a string to the FALLBACK section.

See here for more information.

Type: Boolean Default: undefined

Adds a string to the SETTINGS section, specifically the cache mode flag of the prefer-online state.

See here for more information.

Type: Boolean Default: true

Adds a timestamp as a comment for easy versioning.

Note: timestamp will invalidate application cache whenever cache manifest is rebuilt, even if contents of files in src have not changed.

Type: Boolean Default: false

Adds a sha256 hash of all src files (actual contents) as a comment.

This will ensure that application cache invalidates whenever actual file contents change (it's recommented to set timestamp to false when hash is used).

gulp.task('manifest', function(){
  gulp.src(['build/*'], { base: './' })
    .pipe(manifest({
      hash: true,
      preferOnline: true,
      network: ['*'],
      filename: 'app.manifest',
      exclude: 'app.manifest'
     }))
    .pipe(gulp.dest('build'));
});

  CACHE MANIFEST

  CACHE:
  js/app.js
  css/style
  css/style.css
  js/zepto.min.js
  js/script.js
  some_files/index.html
  some_files/about.html

  NETWORK:
  *

  # hash: 76f0ef591f999871e1dbdf6d5064d1276d80846feeef6b556f74ad87b44ca16a

You do need to be fully aware of standard browser caching. If the files in CACHE are in the network cache, they won't actually update, since the network cache will spit back the same file to the application cache. Therefore, it's recommended to add a hash to the filenames's, akin to rails or yeoman. See here why query strings are not recommended.

Sometimes your assets are served from different source directories. To route these correctly the gulp.src.base option can be used to define a glob's base path. Later multiple streams can be composed with merge-stream, so that one single manifest file is created from them

var path = require('path');
var mergeStream = require('merge-stream');

var config = {
  app: './app',
  tmp: './tmp'
};

mergeStream(
  gulp.src([
    path.join(config.app + '*.html'),
    path.join(config.app + 'assets/*.{png,svg,jpg}'),
    path.join(config.app + 'js/*.js')
  ], {
    base: config.app
  }),
  gulp.src([
  	path.join(config.tmp + 'css/*.css')
  ], {
    base: config.tmp
  })
);
.pipe(plugins.manifest({
  hash: true,
  preferOnline: false,
  network: ['*'],
  filename: 'appcache.manifest'
}))
.pipe(gulp.dest(config.tmp));

for the given file tree

├── app
│   ├── assets
│   │   ├── cover.png
│   │   └── logo.svg
│   ├── index.html
│   ├── js
│   │   └── script.js
│   └── scss
│       └── style.scss
└── tmp
    └── css
        └── style.css

will result in

index.html
assets/cover.png
assets/logo.svg
js/script.js
css/style.css

Sometimes you might want to alter the way paths are passed to the plugin. The correct way will be to provide options to gulp.src so that it generates correct paths.

Say, you have a single folder named public, which is the top-level directory that's served to the browser. In the same directory, you have the css, js and asset files under different directories, along with the html files.

public/
├── assets
│   ├── cover.png
│   └── logo.png
├── css
│   └── style.css
├── js
│   └── app.js
└── index.html